The message, relayed in the form of a flier, was delivered by about 400 off-duty police officers before the Tigers won the first game of their division series against the A’s, My Fox Detroit reported.

As they poured into Comerica Park, fans were given the fliers reading: “Attention: Enter Detroit at Your Own Risk.” It warned that Detroit is America’s most violent city and that the city’s police force is grossly understaffed.

"We're not discouraging people from coming, I love the city, I want them to realize we don't have enough man hours," police union president Joe Duncan told the station. "I don't think the city is going to get same officer 8 hours a day as you do for 12 hours a day."

According to My Fox Detroit, fans also were urged to vote yes on Proposal 2, which would guarantee collective bargaining rights.